Methods for animal anesthesia employing recycling of the gases

Abstract

The invention relates to a method for anaesthetizing animals before slaughter, by the anesthetic action of gases or gas mixtures, operated in “batch” mode, in which the live animals, preferably put together in one or more cages, are placed in a lock chamber for treatment where the animals are brought into contact with anesthetic gas, following a cycle comprising several steps characterized by different contents of anesthetic gas, characterized in that at least one of the steps is carried out using gas recovered from the lock chamber and stored in at least one capacity ( 2 , No. 1 , No. 2 etc.) for temporary storage having a variable volume.

What is claimed is: 
     
       1. A method for anaesthetizing animals before slaughter using an anaesthetic gas or gas mixture, said method operating in “batch” mode in which the live animals, put together in one or more cages, are placed in a lock chamber for treatment where the animals are brought into contact with the anaesthetic gas or gas mixture, following a cycle comprising several steps using different contents of anaesthetic gas, wherein at least one of the steps is carried out using gas recovered from the lock chamber and stored in at least one variable volume temporary storage compartment. 
     
     
       2. The method of  claim 1 , wherein:
 the at least one variable volume temporary storage compartment intended to receive the recovered gas is provided with a bellows system; and 
 recovery of gas contained in the lock chamber is carried out by the bellows system by injecting anaesthetic gas into a bulb operatively associated with the at least one variable volume temporary storage compartment, causing the bellows to rise, thus generating a negative pressure that will allow aspiration of the gas present in the lock chamber, the gas used for actuating the bulb being released subsequently in the lock chamber in order to be reused. 
 
     
     
       3. The method of  claim 1 , wherein there are several compartments for temporary storage having a variable volume, thereby allowing separate storage of different contents of anaesthetic gas in a carrier gas. 
     
     
       4. An installation for anaesthetizing animals before slaughter, by the anaesthetic action of gases or gas mixtures, operating in “batch” mode, comprising a lock chamber for treatment where the animals are brought into contact with the anaesthetic gas or gas mixture and at least one variable volume temporary storage compartment being able to recover gas in the lock chamber and store such recovered gas for later use for anesthesia. 
     
     
       5. The installation of  claim 4 , wherein:
 said compartment intended to receive the recovered gas from the lock chamber is provided with a bellows system, 
 a bulb or jack is associated with said compartment, recovery of the gas contained in the lock chamber being carried out by injecting anaesthetic gas into the bulb associated with the capacity in question, causing the bellows to rise, thus generating a negative pressure that will allow aspiration of the gas present in the lock chamber, the gas used for actuating the bulb preferably being released subsequently in the lock chamber in order to be reused. 
 
     
     
       6. The installation of  claim 4 , wherein said one or more variable volume temporary storage compartment comprises several variable volume temporary storate compartments, thereby allowing separate storage of different contents of anaesthetic gas in a carrier gas.